Kresten Krab Thorup is CTO of Trifork, a public Danish company (trifor.co) providing software solutions to government and financial services providers. Trifork is also creator of the long-running JAOO conference, and co-creator of QCon. As Trifork CTO Kresten in responsible for technical strategy in customer solutions, and spends most of the time acting as internal consultant, researching future technologies, as well as being editor for JAOO and QCon conferences. Kresten has also been a principal contributor to Trifork's own Java EE certified application server "Trifork T4", where he authored the built-in CORBA ORB, a custom Java RMI implementation (now part of Apache Yoko), the transaction manager, the database connection management system, and the Java byte code rewriting subsystem.

Kresten has been a contributor to several open source projects, including GCC, GNU Objective-C, GNU Compiled Java, Emacs, and Apache Geronimo/Yoko. Before joining Trifork, Kresten worked at NeXT Software (now acquired by Apple), where he was responsible for the development of the Objective-C tool chain, the debugger, and the runtime system. Kresten was on the committee for JSR-14 (adding generics to Java) which was closely related to the subject of his Ph.D. thesis.

Most recently, Kresten has founded the Erjang open source project (notice the J there), a virtual machine for Erlang running on the Java Virtual Machine.

Over the last few years, I have been meeting "Erlang people" more and more often, and I was getting this clear impression that "you people" have some kind of magic ability to reason intuitively about concurrent systems in a way that I could not. That bothered me, so I wanted to learn Erlang. Being a language implementor, the most obvious way to do that is to just go ahead and implement an Erlang VM, right?

The result of this "little exercise" is Erjang, an open-source JVM-based Erlang VM, which I think has potential to be useful as a means to push Erlang into new areas of application, help grow the Erlang community, and most importantly make all those Java-heads out there willing to learn how to do concurrency right.

In technical terms, Erjang reads .beam files and compiles them to Java's equivalent .class files which are then read into the running JVM. It runs off a plain Erlang/OTP distribution - requiring only the beam files from there; Erjang itself is written in Java.

To test Erjang, I implemented Triq - Trifork QuickCheck (or triq for short), a free clone of the Erlang QuichCheck which is available as open source. While triq is being developed for the purpose of testing Erjang it is "plain erlang" all the way, with no dependencies on Erjang in any way.

In this talk, I will explain how Triq was used to test Erjang. I will show how Triq works on top of Erlang, while sharing the latest goals and achievements, benchmarks and challenges. I will share what I learned along the way, and demonstrate that Erjang runs well enough to be dangerously useful.